In recent years, numerous security, military, and medical applications have been developed which use Terahertz
(THz) radiation. These developments have heightened concerns in regards to the potential health risks that are
associated with this type of radiation. To determine the cellular and molecular effects caused by THz radiation, we
exposed several human cell lines to high-power THz radiation, and then we determined death thresholds and gene
expression profiles. Necrotic and apoptotic death thresholds were determined for Jurkat cells using an optically-pumped
molecular gas THz source (υ = 2.52 THz, H = 227 mW/cm2), MTT viability assays, and flow cytometric techniques. In
addition, we used confocal microscopic techniques to demarcate lethal spatial regions in a monolayer of dermal
fibroblasts exposed to THz radiation. Then, to determine if cells exhibit a THz-specific gene expression signature, we
exposed dermal fibroblasts to THz radiation and analyzed their transcriptional response using microarray gene chips. We
found that 60% of the Jurkat cells survived the 30-minute THz exposure, whereas only 20% survived the 40-minute
exposure. The flow data confirmed these results and provided evidence that THz-induced cell death was mediated using
both nectrotic and apoptotic processes. The preliminary microscopy studies provided convincing evidence warranting
future efforts using these techniques. Lastly, we found that dermal fibroblasts up-regulated several genes when exposed
to THz radiation. Overall, these results provide evidence for the cellular and molecular effects associated with THz
radiation, and we speculate that the identified up-regulated genes may serve as excellent candidate biomarkers for THz
exposures.